Trace Determination of Zirconium(Ⅳ) by Anodic Adsorptive Voltammetry at a Carbon Paste Electrode

A new sensitive adsorptive voltammetric method was described for the determination of zirconium at a carbon paste electrode (CPE) in the presence of alizarin complexone (ALC). Optimal analytical conditions are: 1.0?0-6 or 5.0?0-7 mol/L ALC, 0. 20 mol/L HAC-NaAc (pH 4.3), accumulation for 60 s at 0 V (vs. SCE), and linear scanning from 0 V to 1.0 V at 250 mV/s. The peak potential of the complex is at 0.81 V. By using a model JP-303 polarographic analyzer, 2.0?0-10 mol/L (S/N=3) zirconium can be detected with a 90 s accumulation, when the 2nd-order derivative linear sweep technique is used, and the linear range is 6.0?0-10-2.0?0-8 mol/L (5.0?0-7 mol/L ALC) and 2.0?0-8-2.0?0-7 mol/L (1.0?0-6 mol/L ALC), respectively. The developed method was applied to the determination of trace zirconium in the ore samples with satisfactory results.

Synthesis, Crystal Structure and Quantum Chemistry Study of Tri(o-bromobenzyl)tin Ferrocenecarboxylate

A novel complex tri（o-bromobenzyl）tin ferrocenecarboxylate has been synthesized and its crystal structure was determined by X-ray diffraction. It belongs to orthorhombic, space group Pbca with a = 1.1340（3）, b = 1.7823 （4）, c = 3.0119（8） nm, V = 6.088（3） nm^3, Mr = 857.81,Z = 8, Dc = 1.872 g/cm^3,μ（MoKα） = 52.63 cm^-1, F（000） = 3328, R = 0.0683 and wR = 0.1057. The tin atom adopts a distorted tetrahedral coordination geometry. Further studies on the title complex have been performed with quantum chemistry calculation at the Lanl2dz basis set level using G98W package. The stability of the complex, some frontier molecular orbital energies and composition characteristics of some frontier molecular orbitals have been investigated.

Determination of Manganese in Tri Calcium Phosphate (TCP) by Atomic Absorption Spectrometry

Tricalcium phosphate Anhydrous Powder typically contains less than 10 ppm (mg/Kg) (w/w) manganese. This level can be determined utilizing Flame Atomic Absorption Spectrometer (AAS) and standard based on known standards. A number of analytical methods are presently used for the analysis of metals in the biochemical. The instrumental techniques available are Inductively Coupled Plasma (ICP/MS), X-Ray Fluorescence, UV-VIS Spectrophotometry, and Atomic Absorption Spectrometry. Flame AA has gained widespread acceptance as an analytical technique and is used for many applications. In this study, we have determined the amount of manganese metal present in Tricalcium Phosphate (TCP) using Flame Atomic Absorption Spectrophotometer. The method has high precision and accuracy. The percent recovery was found to be 99.8% for spiked sample. The results meet the requirement.

Synthesis, Crystal Structure and Quantum Chemistry of Tris[(2-methyl- 2-phenyl)propyl](2,4-dinitro-phenolato)tin

The tris[（2-methyl-2-phenyl）propyl]（2,4-dinitro-phenolato）tin was synthesized by the reaction of bis[tri（2-methyl-2-phenyl）propyltin] oxide with 2,4-dinitrophenol. The compound was characterized by IR, 1H NMR spectra and elemental analysis. The crystal structure has been determined by X-ray diffraction. The crystal belongs to the monoclinic system, space group P21/n with a = 0.9649（0）, b = 1.0087（8）, c = 3.4867（4） nm, β = 90.965（7） , Z = 4, V = 3.3933（7） nm3, Dc = 1.369 Mg·m-3, （MoKa） = 0.796 mm-1, F（000） = 1440, R = 0.0345 and wR = 0.0821. The tin atom has a distorted tetrahedral geometry. The 2D network structure of the complex is formed by hydrogen bonds and π-π effects. The stabilities, orbital energies and composition characteristics of some frontier molecular orbitals of the complexes have been investigated with the aid of G98W software.

To Improve Learning Efficiency,Try This Method

The key to learning a new motor skill—such as playing the piano or mastering a new sport—isn’t necessarily how many hours you spend practising,but the way you practise,according to a 2016 study.Scientists have found that by subtly varying your training, you can keep your brain more active throughout the learning process, and halve the time it takes to get up to scratch.

The current policies on optical disc replication industry in China Abstract of the speech of Wang Yanbin, Deputy Director of Print & Reprecation Industry Management Department of GAPP, on 4th Replication EXPO'02 Conference, Shanghai

Ayear has past since China entried Into the WTO.China is meeting the economical and technicalchallenge worldwide with a more open attitude.As a newmember of WTO.we feel strongly the influence ot theglobal economy.Therefore it is necessary for China toreposition our economy growth point on the referenceframe of global economy system. As other industries,China optical industry is also trying to adjust its positionin the global information industry.Now the policies onChina optical disc industry will be expressed as following,First of all,we must follow the current guidingprinciple on the optical disc replication industrydevelopment. The optical disc industry is a new scientific and tech-nological information industry.The development of

LOOKING FOR THE NEW MJ? TRY THE OLD TD——“Old School”Duncan

The question was on the mind of every NBA fan last January: Whocould possibly be the next Michael Jordan? Turns out the answer wasn t thenew MJ after all. It was the old Tim Duncan. That s old as in... "old school." Duncan s game is built on solidfundamentals, hard work and team play. Just as Doctor Naismith intended. Of course, so was Jordan s game. MJ just preferred to play above therim for the first half-dozen years of his career. before he figured out the

MORPHOLOGICAL DEVELOPMENT OF SCIENCE-INDUS- TRY COMPLEXES IN CHINA

This paper maintains that science-industry complexes (SICs), with science parks as the grassroots units, present a tripartite structure of parks, zones and belts in their spatial layout. In their morphological system, parks act as the building bricks of the zones and belts, while the latter two are the outward expansion of parks, leading to spatial diffusion and the transfer of hi-tech knowhow and hi-tech industry. Viewed from the temporal sequence, a park is the starting point for the growth of a zone or a belt, while a zone or a belt is the evolutionary outcome of parks, reflecting sequential advances of an innovation chain.Based on this viewpoint, this paper attempts to make a case study on the morphological development of hi-tech zones and belts in this country. The paper concludes that there are two developmental patterns which Chinese SICs are destined for. One is a zone that incubates a group of parks and the other is a cluster of zones forming a belt. Such an evolutionary process results from

Life Needs More Goals,and Fewer Complaints

In my opinion,we should have more goals in our lives and have fewer complaints.As is known to all,goals make us go further and prevent us from being lazy.When we have goals,we are encouraged to work hard to achieve them.But if we lose our goals,we may feel uncertain and insecure.For a student,goals do play an essential role in study.I once set a goal to play better in basketball games,and I tried my best to train myself without any fear and hesitation.It was the goal that helped me accomplish my ambition.

A Story About a King of Scotland

I read a story from an interesting book.The story said that once there was a king in Scotland whose name was Robert Bruce.His homeland was occupied by the king of England.He was driven out of his land.He tried six times to fight back but failed.One rainy day,he was tired and sick.When he lay on the ground and was ready to give up,he saw a spider over his head.Six times the spider tried to throw its thread.

Securing the Sea Lanes

Some people,mainly in the West,were taken by surprise when six Chinese warships were seen near the Red Sea in October 2023 amid the conflict in Gaza.Some Western media and politicians tried to frame China’s mission as an escalatory move in the Middle East.

基于Tri-training的半监督SVM

当前机器学习面临的主要问题之一是如何有效地处理海量数据,而标记训练数据是十分有限且不易获得的。提出了一种新的半监督SVM算法,该算法在对SVM训练中,只要求少量的标记数据,并能利用大量的未标记数据对分类器反复的修正。在实验中发现,Tri-training的应用确实能够提高SVM算法的分类精度,并且通过增大分类器间的差异性能够获得更好的分类效果,所以Tri-training对分类器的要求十分宽松,通过SVM的不同核函数来体现分类器之间的差异性,进一步改善了协同训练的性能。理论分析与实验表明,该算法具有较好的学习效果。

结合Tri-training半监督学习和凸壳向量的SVM主动学习算法

为解决监督学习过程中难以获得大量带有类标记样本且样本数据标记代价较高的问题,结合主动学习和半监督学习方法,提出基于Tri-training半监督学习和凸壳向量的SVM主动学习算法.通过计算样本集的壳向量,选择最有可能成为支持向量的壳向量进行标记.为解决以往主动学习算法在选择最富有信息量的样本标记后,不再进一步利用未标记样本的问题,将Tri-training半监督学习方法引入SVM主动学习过程,选择类标记置信度高的未标记样本加入训练样本集,利用未标记样本集中有利于学习器的信息.在UCI数据集上的实验表明,文中算法在标记样本较少时获得分类准确率较高和泛化性能较好的SVM分类器,降低SVM训练学习的样本标记代价.

Optimization for Purification and Characterization of Recombinant Hirudin Ⅲ from E. coli

Aim To optimize purification conditions of recombinant hirudin 3 in thefermentation broth and characterize the product. Methods Reambinant hirudin 3 was isolated andpurified from the fermentation broth by three column chromatography steps with macroporous resin,DEAE cellulose DES2 and preparative RP-HPLC, respectively, and the optimal conditions were obtained.Purity of the product was determined by SDS-PAGE and analytical RP-HPLC. The molecular weight wasdetermined by mass spec-trometry. The structure of the product was analyzed by peptide map.ResultsThe product with purity of 95.4786% was obtained after three purification steps in the optimumconditions with a total yield of 39%. The molecular weight of the product was 6 913.32 ± 6.55 Da,coincident to the theoretical molecular weight of r-hirudin 3. The structure of the product wascoincident to r-hirudin 3 either. Conclusion The optimized purification steps can be successfullyemployed for purification of r-hirudin 3 from E. coli using batch-type approaches. The productobtained with high purity was confirmed to be r-hirudin 3.

基于Tri-training的主动学习算法

半监督学习和主动学习都是利用未标记数据,在少量标记数据代价下同时提高监督学习识别性能的有效方法。为此,结合主动学习方法与半监督学习的Tri-training算法,提出一种新的分类算法,通过熵优先采样算法选择主动学习的样本。针对UCI数据集和遥感数据,在不同标记训练样本比例下进行实验,结果表明,该算法在标记样本数较少的情况下能取得较好的效果。将主动学习与Tri-training算法相结合,是提高分类性能和泛化性的有效途径。

基于Tri-training半监督学习的中文组织机构名识别

针对中文组织机构名识别中的标注语料匮乏问题,提出了一种基于协同训练机制的组织机构名识别方法。该算法利用Tri-training学习方式将基于条件随机场的分类器、基于支持向量机的分类器和基于记忆学习方法的分类器组合成一个分类体系,并依据最优效用选择策略进行新加入样本的选择。在大规模真实语料上与co-training方法进行了比较实验,实验结果表明,此方法能有效利用大量未标注语料提高算法的泛化能力。

基于Tri-Training半监督分类算法的研究

在实际应用中,容易获取大量的未标记样本数据,而样本数据是有限的,因此,半监督分类算法成为研究者关注的热点。文中在协同训练Tri-Training算法的基础上,提出了采用两个不同的训练分类器的Simple-Tri-Training方法和对标记数据进行编辑的Edit-Tri-Training方法,给出了这三种分类方法与监督分类SVM的分类实验结果的比较和分析。实验表明,无标记数据的引入,在一定程度上提高了分类的性能;初始训练集和分类器的选取以及标记过程中数据编辑技术,都是影响半监督分类稳定性和性能的关键点。

基于嵌入式Linux控制台终端驱动程序的设计研究

在Linux系统中,终端设备非常重要,内容十分丰富和复杂,通过终端设备,系统将向用户反馈信息。本文介绍了tty设备的工作机制及体系结构,重点介绍了对tty终端设备的数据发送和接收过程,并在此基础上,进一步举例说明了实现UART设备的tty驱动。

Analysis of Flavone Content in Honey of Pomegranate Flowers

[Objective] The aim was to analyze content of flavones in honey of pomegranate flowers. [Method] Contents of total flavones in 24 honey samples of pomegranate flowers from Mengzi City in 2011 and 2012 were measured as per- spectrophotometry method with acetone as an extractant and rutin as a control. [Result] The average content of flavones in honey of pomegranate flowers was at （2.36±1.36）mg/100 g in 2011 and significantly higher than that in 2012 at （1.71± 0.53）mg/100 g. Analysis was conducted on flavones content in different batches and the results indicated that content of flavones in honey in different batches changed from increasing to decreasing, namely, the content was maximal in peak flowering stage, followed by late flowering stage and initial flowering stage. [Conclusion] The research provides references for development, use and function exploration of the honey of pomegranate flowers.

基于辅助学习与富信息策略的Tri-training算法

针对Tri-training算法利用无标记样例时会引入噪声且限制无标记样例的利用率而导致分类性能下降的缺点,提出了AR-Tri-training(Tri-training with assistant and rich strategy)算法。提出辅助学习策略,结合富信息策略设计辅助学习器,并将辅助学习器应用在Tri-training训练以及说话声识别中。实验结果表明,辅助学习器在Tri-training训练的基础上不仅降低每次迭代可能产生的误标记样例数,而且能够充分地利用无标记样例以及在验证集上的错分样例信息。从实验结果可以得出,该算法能够弥补Tri-training算法的缺点,进一步提高测试率。